GENERAL INFORMATION

1.1 Unit Description. An insert flange unit is comprised of an
insert and bolting ring (flange) and are sold jointly as one unit
unless otherwise requested. Most often, insert flanges are comprised
of a stainless insert and a carbon steel bolting ring, but are
available in other alloys (see 5.0 Materials).

1.3
Code References. Any references to the “Code” are
limited to the ASME Boiler and Pressure Vessel Code, and not other
state or governmental codes which may have jurisdiction.

1.4
Established Criterion. Insert flanges for jacketed piping have
been used extensively by the processing industries for more than
forty years. During these years, insert flanges have established
a standard for dependable service by meeting the demands of critical
jacketed piping systems.

1.5
Insert Flanges Per ASME B31.3. ASME B31.3,
Process Piping, provides requirements for the design of flanges
which are not listed as standards in Table 326.1, of the specification.
These requirements are found in paragraph 304.5.1. This states
that flanges may be designed in accordance with the Boiler Pressure
Vessel Code, Section VIII, Division 1, Appendix 2 or Appendix
Y, depending on whether the gasket OD is inside or outside the
bolt circle. It also states that flanges may be qualified by the
requirements of paragraph 304.7.2. This paragraph applies when
Appendix 2 or Appendix Y are not applicable and states that the
design is to be based on calculations consistent with the design
criteria on B31.3 and substantiated by one or more of the following:

a) extensive & successful service experience
under comparable conditions with similarly proportioned components.
b) experimental stress analysis similar to that described in BPV
Code, Section VIII, Division 2 Appendix 6.
c) proof testing in accordance with ASME B16.9, MSS SP-97, or
BPV Code Section VIII, Division 1, UG-101.
d) detailed stress analysis such as finite element. Since these
insert flanges are very similar to ASME B16.5 flanges, containing
the same ring-type elements, they can be reliably designed to
Appendix 2 of the BPV Code, Section VIII, Division 1.

1.6 ASME Rated. When we refer to an Insert Flange as ASME rated
we are stating that calculations conforming to the ASME Boiler
and Pressure Vessel Code, Section VIII, Division 1, have been
performed which determine minimum flange thickness to meet ASME
B16.5 PSIG at material group 2.2 (see table 1).
These calculations are based on the use of carbon steel to SA-515/516
Gr70 or SA-105 material for the bolting ring and stainless steel
type 304, 304L, 316, 316L to SA-479 or SA-182 for the insert.
The bolting is to SA-193-B7 and the gasket material is spiral
wound. Any changes to the material, bolting, or gasket could change
the required dimensions of the insert flange, if meeting the P/T
rating of B16.5 is desired.

STYLES OF JACKETED
INSERT FLANGES

2.1 Reducing Jacket Insert Flange. This phrase refers to the style
or design of insert flange in which the nominal core pipe size
is smaller than the nominal flange size. The reducing jacket insert
flange style is ideal for systems in which temperature changes
cannot be tolerated at flange connection. By minimizing the distances
at flange connections, it assists in eliminating the frequently
encountered problem of product buildup and solidification at critical
points.

2.1.1 Conventional Reducing Jacket Insert Flanges.
These reducing jacket insert flanges have been used successfully
for decades. This style of insert flange is only available in
class 150 and 300. They utilize the economical advantage of the
ASME B16.5 flange thickness for their design but are not recommended
for critical applications which must meet code.

2.1.2 ASME Rated Reducing Jacket Insert Flanges.
This style of insert flange is available in all classes. On this
style of insert flange calculations conforming to the ASME Boiler
and Pressure Vessel Code, Section VIII, Division 1, have been
performed which determine minimum flange thickness to meet ASME
B16.5 PSIG values at material group 2.2 (see table 1). Therefore
this style of insert flange can be used for ASME Code and Pressure
Vessel Applications.

2.2 Non-Reducing
Jacket Insert Flange.
This phrase refers to the style or design of insert flange in
which the nominal core pipe size is equal to the nominal flange
size. Non-reducing jacket insert flanges require smaller flanges.
Along with the use of smaller valves and other fittings, considerable
cost and space savings in fabricating jacketed systems can be
realized.

2.2.1 Conventional Non-Reducing Jacket Insert
Flanges. These non-reducing jacket insert flanges have been used
successfully for decades. This style of insert flange is only
available in class 150 and 300. They utilize the economical advantage
of the ASME B16.5 flange thickness for their design but are not
recommended for critical applications which must meet code.

2.2.2 ASME
Rated Non-Reducing Jacket Insert
Flanges. This style of insert flange is available in all classes.
On this style of insert flange calculations conforming to the
ASME Boiler and Pressure Vessel Code, Section VIII, Division 1,
have been performed which determine minimum flange thickness to
meet ASME B16.5 PSIG values at material group 2.2 (see table 1).
Therefore, this style of insert flange can be used for ASME Code
and Pressure Vessel Applications.

SIZE

3.1 How to Reference Size. When referencing the size of a jacket
insert flange: First, designate the class and nominal flange size.
Second, designate the nominal core pipe size. If it is a buttweld
style indicate the core pipe schedule. Third, designate the nominal
jacket pipe size with its schedule.

3.2 Nominal
Size. References to the size of a flange, pipe, or bolt is its
nominal size. Use of "nominal" indicates that the stated
size or dimension is only for designation, not measurement.

3.3 Sizes
and Classes Not Cataloged. The sizes and classes are listed due
to their frequency of request and are not meant as a capacity
range. Insert Flanges can be manufactured in all ASME B16.5 classes
and sizes.

MARKINGS

4.1 Bolting Ring or Flange Markings. The edge or outside diameter
of each insert flange is marked in accordance with ASME B16.5
and MSS SP-25; the manufacturer’s registered trademark,
the material’s ASTM or ASME specification grade identification
and the melt identification, rating class and nominal size.

4.2 Insert Markings. The outside diameter of each insert is marked,
as is the bolting ring.

MATERIALS

5.1 Insert Material. Inserts can be manufactured from any machineable
alloy. Inserts of the most popular sizes are stocked in 316L stainless
steel. Other materials which have been used to manufacture inserts
are: carbon steel, other grades of stainless steel, Nickel, Hastelloy™,
AL6XN™, Aluminum, Inconel™, monel, titanium, and Duplex
2205™. The inserts for the ASME Rated Jacket Insert Flanges
for ASME Code and Pressure Vessel Application Flanges are manufactured
of stainless steel to SA-479 or SA-182 type 304, 316, 304L or
316L.

5.2 Bolting Ring/Flange Material. Bolting rings or flanges can
be manufactured from any machineable alloy, but are stocked in
A105 carbon steel. To inhibit rust, the carbon steel bolting rings
or flanges are coated with a black enamel paint. Other coatings,
such as galvanizing, zinc or epoxies, are available upon request.
Other materials which have been used to manufacture bolting rings
or flanges are: stainless steel, nickel, Hastelloy™, AL6XN™,
aluminum, Inconel™, titanium, and other grades of carbon
steel. The bolting rings for the ASME Rated Jacket Insert Flanges
for ASME Code and Pressure Vessel Application Flanges are manufactured
of carbon steel to SA-515/516-Gr70 or SA-105.

5.3 Mill Test Reports. Test reports from the supplier of the raw
material are available upon request. Normally these test reports
are available without cost.

5.4 Material Meeting ASME Code Requirements.
Raw materials are normally manufactured to ASTM standards (e.g.
A-105). We also stock, or can obtain, materials which are dual
certified to meet ASTM standards and the ASME Boiler and Pressure
Vessel Code (e.g. SA-105). This requirement must be made known
when ordering and quoting.

5.5 Domestic Only Requirement. Most raw materials inventoried
are from domestic mills. If domestic material is required, this
requirement must be made known when ordering and quoting to assure
receiving "domestic only" material.

FACINGS

6.1 Flange Facings. Insert flanges are manufactured with a standard
raised face to ASME B16.5 dimensions. This is the facing that
will be supplied unless otherwise specified. Other flange facings
can be ordered. These include, but are not limited to, large male
and female, small male and female, large tongue and groove, and
small tongue and groove. Due to the two piece design of the insert
flange a flat face insert flange cannot be offered.

6.2 Raised
Face Dimensions. Inserts are manufactured with a raised face thickness
equal to the corresponding ASME B16.5 dimension. The diameter
of the raised face on the inserts are equal to, or greater than,
the corresponding ASME B16.5 dimension. Larger raised face diameters
are found on a few of the non-reducing jacket flanges. This is
necessary when a jacket pipe’s inside diameter is greater
than the standard ASME B16.5 raised face dimension. However, in
all cases there is adequate bolting clearance.

6.3 Flange
Facing Finish. Standard facing finish for the gasket surface of
the insert is a continuous spiral or phonographic finish to an
average roughness in the range of Ra 125 to 250 µin. This
is the facing finish that will be supplied unless otherwise specified.
Other surface finishes for flange faces can be ordered. These
included, but are not limited to, specified smooth or unpolished
finishes (e.g. Ra 32, 63, 125, 250, or 500 µin.), or a concentric
serrated surface.

PRESSURE TEMPERATURE RATINGS

7.1 ASME Boiler and Pressure Vessel Code calculations
To establish Maximum Allowable Working Pressure (MAWP) for the
Conventional Jacket Insert Flanges. Due to the differences between
these insert flange designs and standard ASME B16.5 flanges, calculations
were performed to establish an MAWP Table . In some cases, values
exceed the ASME ratings, and in others, values are below the ASME
ratings. These calculations conform to the procedures detailed
in Appendix 2 of the ASME Boiler and Pressure Vessel Code, Section
VIII, Division 1. They were based on the use of standard 1/8"
thick asbestos-equivalent gaskets and carbon steel bolts to SA-307
B. Flanges are forged carbon steel to SA-105 and inserts covered
by these ratings may be type 304, 316, 304L or 316L. The MAWP
on standard insert flanges have been established without calculating
for flange protection due to overbolting using SA-193-B7 bolts.
The ASME code has specifically allowed the use of alloy steel
bolts to SA-193-B7 with ASME B16.5 flanges without calculation.
This is primarily because ASME B16.5 flanges cannot always meet
the overbolting protection requirements of the code, due to extremely
high bolt strength. Since the bolting and flange thickness of
conventional insert flanges are identical to those of ASME B16.5.,
but do not share the code’s exemption, MAWP was calculated
using carbon steel bolts to SA-307 B. For piping systems using
SA-193-B7 bolts, that must meet the ASME Code requirements, we
have designed insert flanges which meet code requirements. (see
2.1.2 and 2.2.2)

7.2 Use of the ASME B16.5 Maximum Allowable Working Pressure (MAWP)
for ASME Rated Jacket Insert Flanges.
The ASME B16.5 Pressure Temperature Ratings at material group
2.2 (see Table 1) can be used for the Jacket Insert Flanges marked
"ASME Rated", for ASME Code and Pressure Vessel Application.
Calculations conforming to the ASME Boiler and Pressure Vessel
Code, Section VIII, Division 1, have been performed which determine
minimum flange thickness to meet ASME B16.5 MAWP. These calculations
are based on the use of carbon steel to SA-515/516 Gr70 or SA-105
material for the bolting ring and stainless steel type 304, 304L,
316, 316L to SA-479 or SA-182 for the insert. The bolting is to
SA-193-B7 and the gasket material is spiral wound. Any changes
to the material, bolting, or gasket could change the required
dimensions of the insert flange.

7.3 Jacket Pipe Pressure. References to pressure temperature are
limited to the pressure temperature of the process pipe. Insert
flanges are not a limiting factor to the pressure of the jacket
pipe.

WELDING DESIGN FEATURES

8.1 Process Pipe Weld Design. Insert flanges are featured with
optional slip-on or buttweld designs. These represent the most
requested options, but are not the only options available. Insert
flanges can be manufactured with socketweld, threaded, roll-on,
and tapered bores. Bore diameters are manufactured to ASME B16.5
dimensions for use with pipe to ASTM, API, and ASME standards.
Insert flanges can be manufactured with bores to accommodate tube
sizes.

8.1.1 Slip-on. Reference to slip-on as a type of jacket insert
flange indicates that the insert will slip over the process pipe
to allow front and back fillet welds. (see drawing A) If a back
fillet weld is required, one end of the spool must have a section
of pipe which is split and welded, or clamshell constructed.

8.1.2 Buttweld. Reference to buttweld as a type of jacket insert
flange indicates that the insert will buttweld to the process
pipe, allowing a full penetration V-groove weld. (see drawing
"B") The welding end for the process pipe of the buttweld
insert flange has a welding bevel and root face conforming to
ASME B16.9 and B16.5 (see Welding Ends).8.2 Jacket Pipe Weld Design.
The design of the insert at the area for the jacket pipe weld
attachment varies according to the style of jacketed insert flange.
8.2.1 Reducing Jacket Insert Flanges, Jacket Pipe Weld Design.
To accommodate the jacket pipe there is a 1/4 to 3/8 inch hub,
machined for the specified jacketschedule. This allows for a fillet
weld to the back of the insert. (see drawing "A" and
"B")

8.2.2 Non-Reducing Jacket Insert Flanges, Jacket Pipe Weld Design.
The non-reducing design of the insert at the area for the jacket
pipe weld varies according to the size and schedule of the jacket
pipe (see Non-Reducing Hub Designs). The determining factors are
the clearance or distance between the nuts and the inside of the
jacket pipe. These factors determine not only the design but also
the length of the insert and the diameter of the raised face (see
6.2 Raised Face Dimension). To accommodate the jacket pipe there
is a 1/4 to 3/8 inch hub, machined for the specified jacket schedule.
This allows for a variety of fillet welds. The insert hub is designed
with a stopping point or mark to indicate the intended gasket
face to jacket pipe dimension.

HOW TO FABRICATE JACKET INSERT
FLANGE ASSEMBLIES

9.1 Prepare Pipe and/or Weld Process Pipe.

9.1.1
Slip-on Insert Design. Measure, cut, and prepare process and jacket
pipe. With bolting ring/flange and insert assembled, slip process
pipe into insert and front weld end of process pipe at point A.
If required, back weld process pipe and insert at point B. The
assembly will require clam-shelling (see 9.3) a section of the
jacket pipe if the process pipe is back welded.

9.1.2 Butt-Weld Insert Design. Measure, cut, and prepare process
and jacket pipe. With bolting ring/flange and insert assembled,
align process pipe to welding end of insert and weld. The assembly
will require clam-shelling (see 9.3) a section of the jacket pipe
when buttwelding the process pipe.

9.1.3 Transit
Hub. As an alternative to clam-shell construction, we offer an
optional transit hub for the jacket pipe. A transit hub allows
the jacket pipe to slide further along the hub, thus allowing
access to the welding area of the process pipe at the other end
of the spool. If this is the preferred method of fabrication,
specify this requirement when ordering. There may be an additional
charge for modification. See picture to the right.

9.2 Weld Jacket
Pipe. Slip jacket pipe over insert hub and weld at point C. When
space allows, you may pull the bolting ring/flange back over jacket
pipe to facilitate welding.

9.3 Clam-Shell.
After welding process pipe to insert at point B, put clam shell
section of jacket pipe into position and weld together. See Clam
Shell drawing.

9.4 Align
and Bolt. Rotate the bolting ring/flange to align it with its
mating flange and bolt them together.

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